Piston-valve for locomotives.



J. P. CHADWICK. PISTON VALVE FOR LOCOMOTIVES.

APPLICATlON FILED JULY I? 1917.

Patented Nov.

2 SHEETS-SHEET 1- ITl U In awn $022 J. P. CHADWICK. PISTON VALVE FOR LOCOMOTIVES.

APPLICATION FILED JULY 17. 1917.

Patented Nov. 6, 1917.

2 SHEETS'SHEET 2.

JOHN P. OHADWICK,

0F ALEXANDRIA, VIRGINIA.

PISTON-VALVE FOR LOCOMOTIVES.

Specification of Letters Patent.

Patented Nov. 6, 191?.

Application filed July 17, 1917. Serial No. 181,073.

.To all whom it may concern:

Be it known that I, JOHN P. OHADWICK, a resident of Alexandria, Virginia, have invented certain new and useful Improvements in Piston-Valves for Locomotives, of which the following is a specification.

My invention is designed to provide for the use of a piston valve on locomotives in the place of the ordinary slide valve by substituting for the slide valve chest a steam chest adapted to receive a piston valve so that the locomotive may use super-heated steam.

My invention relates to the details of construction whereby the substitution may be made with the least change and consequent economy and without impairing the eiricieucy of the substituted chest and valve.

My aim has been that all studs for fastening the steam chest to the cylinder shall be on the outside of the steam chamber and therefore easily accessible, and at the same time being outside of the steam chamber the studs and nuts are not subject to leakage under the pressure of the steam.

I have found in practice that it is of great importance that all necessity for radical changes in the valve gear be obviated and that in this connection it is important that the piston valve chest shall'not be of undue length and to this end I utilize depressed heads fitting the ends of the cylinder chest which permits me to use a chest of the same length as the slide valve chest.

I make the valve chamber of segmental transverse sections so as to provide a circumferential unrestricted steam passage permitting the use of a smaller valve which is decidedly advantageous due to the saving in lubricant and powe Another important change in my construction is in the construction and arrangement of the bushing which is provided with a shoulder bearing against the forward face of the steam chamber and the depressed head maintains the bushing in place through the ressure of an interposed gasket.

T e cylindrical form of the chest and the depressed head permits of ready examination of the interior by the removal only of the end casing and the head.

In the accompanying drawings illustrating my invention,

Figure 1 is a side elevation of the chest partly in section and partly in elevation;

Fig. 2 shows partly an end view partly a sectional View; I

igs. 3, land 5 are detailed views shown enlarged from the scale of the other figures.

The chest a is of the shape shown in Figs. 1 and 2 and with its piston valve b is of a construction generally well known operating in the usual manner. In order to render unnecessary radical changes in the valve gear I aim to make my improved chest of the same length as the slide valve chest for which it is to be substituted and in order to secure this very material advantage I use depressed heads 0 and apply the fastening studs on the outside of the steam chamber thus enabling a shortening of the chamber to the length of the usual slide valve chest and at the same time remove the studs from the detrimental eifect of being within the steam space. The bushing d I provide with an enlarged head shown at e and this fits a shoulder f and limits the inward movement of the bushing. A copper gasket 9 is inserted between the outer face of the bushing and the recessed inner end of the head so that as the head is secured in position it bears against the gasket and through the gasket upon the bushing to hold it securely in place. As shown in Fig. 2 I use short studs h to secure the outer flange in place and at the ends of the base section I form recesses 71/ for the reception of the studs, and their nuts thus permitting the bushing to be slid in over the nuts and the end sections to follow the bushing. The end sections are held in place by bolts 71. A cap k is held by a bolt m provided with a suitable nut. It will be seen that the cap is can be readily removed as can also the head 0 to gain access to the interior.

I provide ribs n to support the sheet metal casing 0, which is fastened in place by the headed screws 7?.

What I claim is A iston valve steam. chest having a bushing t ierein, a depressed head for holding the bushing in place, and a base flange for said chest adapted to receive studs and end studs located outside the steam chest in de ressions formed in said flange beneath sai deressed head to permit the'passage over said studs of the bushing and the heads, substantially as described.

In testimony whereof I afix my signature.

JOHN P. CHADWICK.

and I 

